Re: Relationals vs. Objects Databases I

In article <34CF578C.7751_at_ipipan.waw.pl>, Kazimierz Subieta <subieta_at_ipipan.waw.pl> writes
>Karl & Betty Schendel wrote:
>>
>> On 27 Jan 1998 19:11:11 GMT, "Richard Ronteltap" <rontltap_at_euronet.nl> wrote:
>>
>> >>>I think a database programming language should be capable to to
>> >>>all of the work.
>> >>In principle I do agree, and theoretically SQL is capable of this.
>> >
>> >No. SQL is *theoretically* incapable to do all the work because it
>> >is no computationally complete. (Has to do with Turing machines).
>> >
>> >For example: Tell me the SQL statement that gives the top 100
>> >most expensive products in a product table with name and price
>> >attributes.
>>
>> Bzzt! Wrong challenge. You can do that one in SQL, although it will
>> probably run like frozen dogshit.
>> select product from prod_table p1
>> where 100 <= (select count(*) from prod_table p2
>> where p2.price > p1.price)
>
>Right challenge, wrong example.
>Imagine all prices are equal and we have 1000 products.
>Your query returns no tuple. Richard wants 100 (random) tuples.
>Right?
>
>Of course, your example is wrong in all other cases,
>but this is evident.

Richard wasn't *that* specific about his requirements.

Personally, I was fully aware of this and other possible shortcomings of the solution I gave, and how to overcome them.

-- 
Jeremy Rickard

(To email, change "SPAM" to "jbdr" in address.)